Tag: Tent Caterpillars

Winter weather in Wisconsin is anything but predictable. It’s not consistent either. In fact, the only true statement you can make is that the weather is interesting. Exciting might work as another term for it. So, I’m not at all surprised that November turned out quite cold with temperatures well below normal, and now December is turning out a bit warm. In fact, we’ve had a number of days that have been above freezing. From a personal perspective, I’m not complaining even a little. My wood pile continues to look nice too. In fact, the house got a bit too warm last night using the minimum amount of wood. I may not even start a fire this evening given that I used one this morning to dry my clothes (hey, driers cost money to operate—clothes racks are pretty much free except for the initial investment).

Just because I personally like the weather though, doesn’t mean there aren’t concerns. When the weather is like this, the ground doesn’t freeze completely. Bugs that are overwintering in the ground and on plants aren’t killed off when the weather is too warm. In fact, I’m thinking if the weather doesn’t get colder soon, I may end up with a bumper crop of tent caterpillars this spring.

Even though people don’t like the cold winds of winter, the plants need it to remain viable. Nature has evolved to require the presence of extreme cold in order to keep insects under control. When the insects aren’t controlled, the plants have a hard time surviving (normally it’s the plants you want most that die the easiest). For example, tent caterpillars can easily strip my plum trees and because the trees don’t get a second set of leaves, the trees are bald for the entire summer (resulting in their death).

Unfortunately, the weather can also get too cold. Last winter we experienced day after day of colder than usual temperatures. The result was that about half of my grape vines died. Interestingly enough, the grape roots survived and new vines came up from the root. I’ll still have to wait for three or four years to get my first batch of grapes from the new vines, but it won’t be as long as if I had to replant them using new plants. The point is that there is a range of temperatures that plants expect during the winter months and when those temperatures aren’t met, the plants die or the insects overwhelm them.

A number of people have asked where global warming is given the temperatures we’ve been having for the most part. Global warming is a technically correct, but misleading term. The more I read, the more I come to understand that the overall warming of the earth’s temperature causes wider variations in climate, not necessarily overall warming. While we have experienced colder weather here in Wisconsin, overall, the earth has continued to warm. I was reading about the effects of the warming in other areas of the world just this morning.

I’ll eventually provide some additional input regarding global warming because there seems to be a great deal of confusion about things. I do believe there is some level of global warming based on the weather I’ve seen personally. Whether global warming is due to natural climatic variations or the result of mankind’s mistreatment of the planet remains to be seen (although, fouling the planet’s atmosphere, water, and soil is a bad idea no matter what the effect might be). No matter the cause, I look for the effects to become more prominent in the future. Let me know your thoughts about our interesting winter weather at John@JohnMuellerBooks.com.

A lot of the documentation I read about tent caterpillars online says that they’re relatively harmless, which is true when they appear on certain kinds of trees. However, when it comes to fruit trees, tent caterpillars can become a horrible problem. In fact, tent caterpillars nearly killed our plum trees (which are still recovering three years later).

The problem is one of tree growth. A lot of trees get a secondary growth of leaves. When the tent caterpillars do their job during the mid-spring to late-spring months, they damage the first growth of leaves. The trees can recover with the secondary growth. However, many fruit trees get just one set of leaves for the entire summer, so when the tent caterpillars damage them, the tree is stripped for the summer and can’t store enough energy for the winter months.

Tent caterpillars also tend to strip fruit trees, partly because they’re smaller than some of the other trees that are affected by them. In fact, that’s what happened to our plum trees. The foliage was stripped before we knew what was happening and the trees simply didn’t recover. After viewing other trees the tent caterpillars have attacked, it becomes obvious that they really are just a pest at times.

Part of the solution is to inspect the trees carefully during pruning. Unfortunately, even a close inspection won’t reveal all the tent caterpillar clusters and some hatch. During the spring months I take regular tours of the orchard to look for the tent caterpillar nests, especially during the early morning when the night moisture reveals the nests with greater ease. (The inspections are also good exercise and are quite pleasant, so it’s not really work in the traditional sense of the word.) I hand pick the caterpillars and ensure I crush them. Removing them from the trees simply invites them to come back later.

The trees that seem most affected by tent caterpillars are plums and apples. Cherries are also affected, but the tent caterpillars haven’t acquired a taste for the Mesabi cherries for whatever reason (the yellow-bellied sapsuckers tend to avoid them as well). Untouched are the pears, which don’t seem to attract nearly as many pests at other trees on our property do.

A proactive approach to dealing with tent caterpillars is essential if you want to maintain tree vitality. Make sure you take that walk each day to mellow out, improve your health, and keep your trees healthy. Let me know your thoughts about tent caterpillars at John@JohnMuellerBooks.com.

In Trimming the Trees (Part 2) I discussed some of the specifics of pruning trees. At this point, my trees are all pruned. However, there is still work to be done. For one thing, this is the time of year when I examine the trees for egg masses of the Eastern Tent Caterpillar. Despite what you may have heard, repeated infestations will definitely kill a fruit tree, especially if the infestation is severe enough. It only makes sense. If you remove all of the leaves from a tree that only gets one set of leaves per season, the tree can’t store energy for the winter months.

Our experience has been that they’re a nuisance with apple trees. Yes, the tent caterpillars will cause a problem, but if you get in there and squish all of the caterpillars in the tent (or better yet, get rid of those egg masses in the spring), the apple hardly notices. However, plum trees seem to attract tent caterpillars like magnets. All four of our plum trees were in danger from dying at one point because we simply couldn’t keep the caterpillars under control.

We did try a number of sprays—all of which proved ineffective. Spaying the trees with a dormant oil spray in the spring helps only a little. By far the best strategy is to hunt down the egg clusters and destroy them. The secondary strategy is to look for the tents absolutely every day in the spring and summer after the trees have leafed out and destroy them by individually squishing the caterpillars by hand. We actually had two of our plum trees stripped of leaves in a single day by these pests.

While we’re looking for tent caterpillar egg clusters, we also look for other problems in the trees, such as disease, insect infestations, and so on. It’s easier to find problems after you’ve pruned the trees and there are fewer branches to check. Taking time now to check the trees will save you a lot of effort later.

Of course, now we have a pile of branches to deal with. This year we pruned our pear trees heavily because they’ve become a little overgrown. If pear trees get too overgrown, they’ll tend to prune themselves in heavy winds—usually not in a way you would have chosen. The pile of branches from all of our trees is quite high this year.

We’ll put all of these branches through the chipper and then use them for mulch. A lot of people would probably burn the branches up, but using them for mulch does save at least some money. I’ve been trying to figure out the environmental balance in this case. On the one hand, burning the branches would produce a lot of particulate smoke that would pollute the air for at least a while. However, using the chipper also produces pollutants, and some of those pollutants are harsher on the environment than the smoke from burning would cause.

If we had burned the branches, I would have placed the pile in the middle of the garden. That way we could have plowed the ashes into the ground where they would have provided fertilizer on top of the winter rye you can see growing in the background of the picture. So, either way, the branches wouldn’t have gone to waste. However, we really need the mulch more than the ashes, so we’re creating the mulch.

Our orchard is ready for spring at this point. Let me know about your tree pruning and bug eradication experiences at John@JohnMuellerBooks.com.